MNN - Mother Nature Network

Kids love to watch plants grow, especially when they've played a role in choosing and establishing them. Terrariums are a great indoor craft project, allowing kids to create their own unique miniature gardens enclosed in glass or plastic. From selecting the plants and containers to finding a special place to display it in the home, building a terrarium is an engaging way to get kids excited about nature.

Building a terrarium is an easy five-step process.

1. Choose a container. The basis of your terrarium could be a fish bowl, a mason jar or a bottle; be creative. Terrariums can be open or closed, so it's up to you whether your container will have a lid, but open terrariums are easier to maintain.

2. Select your plants. A closed terrarium will provide a warm, moist environment that's ideal for tropical plants that thrive on humidity and indirect light. Your best bet will be plants that won't grow too large, or too quickly. Options for a closed terrarium include ferns, bromeliads, miniature begonias, Swedish fig, oxalis, fittonia, baby tears, pilea and carnivorous plants like pitcher plants, venus fly traps and sundews. Open terrariums won't build up humidity in the same way, making them ideal for low-maintenance succulents, which require very little water.

3. Prepare your terrarium for planting. Spread 1-3 inches of pea gravel on the bottom of the container, which will allow for drainage. Then add 1/2 inch of activated charcoal, which can be found in the aquarium section of pet stores. This layer acts as a filter to purify the air and water inside the terrarium. Next, spread a thin layer of sphagnum moss on top of the charcoal, which keeps the soil in its own separate layer. Finally, add a layer of soil mix consisting of one part coarse builder's sand to two parts sterilized potting mix, such as Miracle-Gro Organic Choice Potting Mix. Moisten this mixture before adding it to the container.

4. Add your plants and decorative items. Create planting holes in the soil with small hand tools. Remove your plants from their pots, gently break up the rot ball and place the plants in the holes, tamping down the soil around them. Vary the plants in height and color for an interesting visual effect. Kids will love adding small items like shells, figurines and even toys to personalize their terrariums.

5. Keep your terrarium balanced. Terrariums require a minimum of care, and the closed varieties rarely need to be watered, as condensation collects on the glass and drips back down onto the plants. Keep your terrarium in indirect sunlight, as bright light will cause it to get too hot inside. Fertilizing the plants too often could cause them to grow too large for the container, but if they seem like they could use a little help growing, you can use a 1/4 strength solution. Trim plants as needed to keep them appropriately sized, snipping leaves that touch the glass.